Simple explanation of voltage please

So I've been teaching myself more about board level repair and never took the time to properly learn basic electrical concepts such as voltage. Just about everything makes clear sense but voltage to me.

I've read about 50 different (what feels like) definitions online, as well as on youtube.

3 Answers

Stephen Elliott electric current is the flow of electrons in a conductor. Voltage is basically how hard those electrons are being pushed down that conductor. The number of electrons per second going past a specific point is the current which is measure in amperes. Think of it like water pressure. If you use the "standard" analogy of water flow, amp's are like gallons per minute. With more water pressure (voltage), you get more gallons per minute (amps) going past a point.

Hope that explains it a bit. Good place to start learning would be right here

Paradoxically enough, water or hydraulics to be specific and electricity react to barriers and loads in much the same way. A garden hose presents resistance to flow even with no kinks. Lay it out in a straight line and with nothing attached water will freely flow out the other end. Or does it? The hose itself much like wire causes a resistance to the flow, however minute it may be. If you rolled the hose up and turn on the water again the coiled hose will create even greater resistance. If this was an electronic circuit that coil of wire could be called a choke because it causes a choking affect in AC circuitry like analog radios or a Crossover in a speaker.

Now the hose gets a cut or breaks and you opt to repair it. The coupling that you use will cause additional resistance to the flow. For arguments sake we'll say your coupling was for a smaller hose. That coupling becomes an orifice restricting the flow even greater creating a significant pressure drop across the coupling than it would if you had a larger one. In fact a pressure gauge used for measuring this will be connected to both sides of the coupling with two connectors and the indicated pressure Will be the difference in potential (pressure drop or 'Delta P'). In electronics that coupling is a resistor and your DMM (digital multi meter) is your pressure gauge. By placing a test lead On both sides of the component you will read the Delta V, or voltage drop as it is referred to.

I hope this helps. Now a word from the safety team. Household current is very dangerous. You may hear electricians talk about getting bit and not really emphasizing the gravity of what COULD HAPPEN. Electricity flowing through your body creates a wound path for lack of a better explenation from the point of entry to exit burning tissue and breaking bones. I highly recommend skills training to at least recognize what hazardous voltage circuits look like. IE your microwave oven plugs into 120vAC bit the voltage that does the cooking is stepped up to 10kv or 10,000 volts. Most test ewuipment will be rated for use up to 600 volts. If you put your DMM on 10kv it will straighten your legs so fast it will launch you across the room. Th sudden stop can cause spinal injury or worse. I have personally witnessed it and yes, he was smoking.

Electric charges of the same sign repel each other, while electric charges of different signs attract each other. Electrons(-) repel electrons(-). Electrons(-) attract protons (+). Those charges need no medium to transfer this force. Vacuum is enough for an electric charge to 'feel' the other electric charge.

A power supply usually has two wires coming out of it, or two terminals to connect wires to.

The power supply acts as if it is putting more electrons on one terminal than on the other terminal.

When you connect a wire between the terminals, electrons from the wire will be repelled by the terminal with more electrons and attracted to the terminal with less electrons. It will feel this force and move, and his movement can do work.

The more electrons one terminal has than the other terminal, the bigger the force this electron will 'feel'. Bigger forces can accelerate electrons to higher speeds. This is proportional to the voltage.

Imagine buzzilions of electrons repelling together a electron on the wire. This electron will be able to do a lot of work before reaching the other terminal of the power supply.

Now if you have only a few electrons more on one electrode than on the other electrode, the wire electrons won't be pushed too hard by them and will not be able to do much work, which means less voltage.

This analogy only serves for a DC power supply. In the case of AC power supplies, like the wall outlets, the charge difference between power supply terminals oscillates from one terminal to another around 50 times per second due to the way power generators work. But that is another question.